We tried moving to the new glib in r17849, then downgraded the python2 / gtk2 moduleset back to the version requiring this patch in r17910 (+ r17913 for gi).
The patches were mirrored in our repo since r17912, but a few didn't make it (including this one - maybe the urls went 404 and those ended up being the contents?).

Anyway, maybe it is worth trying glib 2.50 or 2.52 again?

lzo isn't being built before python-lzo can be fixed quickly by jhbuild buildone lzo

Saw this too, we already have <after>lzo</after> in the python-lzo module, maybe I misunderstand what "after" means then?
Anyway, I did the same thing (jhbuild buildone lzo) and moved on.

Regarding python3 support, here's the reply from jralls on gtk-osx-devel: ​Re: python3 modules.
I'm trying to get my head around this one, smo: what do you think we should do about this? at least the after thing?